Method for rock-chiseling

ABSTRACT

The invention relates to a method for opening rock with a chisel, especially for producing a drillhole in rock by means of a drilling device that comprises a percussion drive and a rotating thrust rod assembly. The percussion unit, via the drill head, exerts a thrust impulse on the breast in a segment thereof in order to knock out rock from the breast. In a subsequent step, the percussion unit is rotated by an angle α via the rod assembly. Pieces of rock are knocked out from the breast by exerting thrust impulses via the drill head and the drill tip in the corresponding new segment of the breast.

[0001] The invention relates to a method for opening stone or rock with a chisel, in particular for producing a drillhole in rock for light to medium rock formations, and claims the priority of the German patent application 101 01 708.1, to the content of which reference is made.

[0002] When drilling in relatively light to medium rock formations, use is normally made of “MUD motors”, as they are known. These are screw motors which operate on the Moineau principle.

[0003] Drilling with MUD motors is complicated in operational terms and expensive so that, as compared with drilling in loose stone formations, which is possible without the use of MUD motors, a cost factor of 5 to 10 arises.

[0004] In order to avoid the use of the expensive MUD motors, smaller hard rock drill heads from mining and anchor technology have been used, but these do not permit any controlled forward drive.

[0005] In addition, controllable, asymmetric hard rock drill heads with what are known as double taper drilling rod assemblies, developed by the FlowTex company, have been used. The vertically asymmetrical wing cutters of the drill heads used in this case were moved, under control, in such a way that the longer front cutter works into the rock in the desired direction as a result of short left/right pivoting movements. After an appropriate pilot drilling depth, by means of rotation of the entire drill head, the drillhole diameter is then machined out by means of a pilot cutter and a reamer. In this case, the pilot cutter represents the longer front cutter and the reamer represents the shorter front cutter.

[0006] This method also entails high costs, since the required double taper drill rod assemblies are expensive. In addition, the drilling device has a poor efficiency, so that only short drilling distances can be implemented with the expenditure of a great deal of time. In this case, pilot cutting in order to change direction is complicated, and the wear on the pilot cutter is high. In practice, the pilot cutter needs to be changed after every drilling operation.

[0007] The invention is, then, based on the object of providing a method for drilling stone or rock with which cost-effective and high-performance stone or rock drilling is possible.

[0008] Furthermore, it is an object of the invention to provide a device suitable for the method.

[0009] The invention is achieved by the subject matter of the independent patent claims. Advantageous developments are the subject matter of the subclaims.

[0010] The method according to the invention is based on the idea, with the aid of an asymmetric rock drill head with preferably integrated, asymmetrically arranged jet nozzles and a drilling device which can be driven forward with percussion and roration, to use a combination of rotation and impact in such a way that, by means of—preferably high-frequency—percussive pulses, pieces of stone are broken out from a specific circular section of the workface and, after a certain preferably short—period of time or a certain—preferably low—penetration depth of the asymmetric chisel, the asymmetric chisel is rotated through a specific angle, in order to move the chisel head into a new circular section of the workface and then, with the aid of the percussive pulses, to break pieces of stone out of the new angular range. The asymmetry can also be implemented by means of a specific (for example geometric) nozzle arrangement or jet alignment, without the tool as such being asymmetric.

[0011] This procedure permits surprisingly smooth drilling advance in rock or stone with a simple rod assembly drilling device and an additional percussion drive, using a simple asymmetric drill head and, in the process, by varying the drill parameters, such as the residence time in a specific angular section, and therefore nonuniform distribution of the forward drive force onto the workface, directional drilling.

[0012] The device according to the invention makes it possible to avoid a wedging effect and the associated undesired distribution of the introduction of force away from the tip of the drill head. In order to increase the percussive force further, the tip of the drill head can be designed to be movable, such that the entire percussive pulse is introduced into the tip of the drill head without energy being used to accelerate the rest of the drill head.

[0013] The percussion unit is preferably operated at a high percussive frequency—particularly preferably at more than 1000 impacts/min.

[0014] A variable thrust force is preferably applied to the drill head via a rod assembly.

[0015] The steps of impacting and of rotation can be carried out with a cyclic change. The angle β can be 0° or 360° for steering, while it is otherwise preferably 0° C. and 90°.

[0016] Asymmetric drill heads have proven to be particularly advantageous for use in accordance with the method of the invention.

[0017] In order to force the forward drive further, drilling media for cooling or cutting or removing the debris can be arranged via nozzles arranged asymmetrically in the drill head or chisel.

[0018] In the following text, the invention will be explained in more detail using an exemplary embodiment illustrated in the drawing.

[0019] In the drawing:

[0020]FIG. 1 shows an illustration of the workface with the drill head located in it in three drilling steps and

[0021]FIG. 2 shows a detailed view of the drill head from FIG. 1.

[0022] The drilling device 1 has a percussion unit 2, an asymmetric drill head 4 and a connection for a rod assembly 6. Via the rod assembly 6, both a torque and a variable axial pressure can be transmitted to the drilling device 1. During drilling (as illustrated in FIG. 1), the drilling device 1 with the drill head 4 is in the workface 8. The chisel point 10 of the drill head 4 is mounted such that it can move, so that the complete percussive pulse from the percussion unit 2 is transmitted to the chisel point.

[0023] A channel 12 for a drilling medium emerges in the front region of the chisel point 10. The axis of the chisel point 10 is at an angle α with respect to the axis of the drilling unit.

[0024] As a result of operation of the percussion unit 2, a region of the stone is broken out of the workface 8 with the chisel point 10 (FIG. 1). In the process, a variable thrust force is exerted on the drilling device via the rod assembly 6. In a next step, the drilling device, and therefore the drill head, is rotated through an angle β, in order in this position to knock a piece of stone out of the workface with the aid of the percussion drive 2 in a new region of the workface 8. For the purpose of steering, the angle is 0° or 360°, particularly good forward drive being achieved with the latter. 

1. A method for opening stone or rock with a chisel, in particular for producing a drillhole in rock with a drilling device having a percussion drive, a rotary/thrust rod assembly, characterized in that the percussion unit (2) exerts a percussive pulse on the workface via the drill head (4) in a circular area section of the workface (8), in order to break stone out of the workface, and, in a next step, the drill head (4) is rotated through an angle β and, in the corresponding new circular area section of the workface (8), again by means of percussive pulses via the drill head (4) and the chisel point (10), pieces of stone are broken out of the workface (8).
 2. The method as claimed in claim 1, characterized in that the drill head (4) is moved back counter to the forward drive direction in order to reach the new circular area section.
 3. The method as claimed in claim 1 or 2, characterized in that the percussion unit (2) is operated at high frequency, preferably at a frequency of more than 1000 impacts/min.
 4. The method as claimed in one of the preceding claims, characterized in that a pressure is exerted on the drilling device, and therefore on the drill head (4), via the rod assembly (6).
 5. The method as claimed in claim 4, characterized in that the pressure is variable.
 6. The method as claimed in one of the preceding claims, characterized in that the steps of impacting and of rotation are carried out with a cyclic change.
 7. The method as claimed in one of the preceding claims, characterized in that the angle β is 0° to 90°.
 8. The method as claimed in one of claims 1 to 6, characterized in that the drill head is rotated via the rod assembly (6).
 9. The method as claimed in claim 1, characterized in that the variation of drilling parameters, such as angle and/or pressure and/or cycle duration, is used in order to achieve a specific drilling direction.
 10. The use of a drilling device having a drill head (4) with an asymmetric geometry in a method as claimed in one or more of the preceding claims.
 11. The use as claimed in claim 10, characterized in that the drill head (4) has a movable chisel point (10).
 12. The use as claimed in claim 10 or 1, characterized in that the movable chisel point (10) exerts a percussive pulse on the workface in the steering direction.
 13. The use as claimed in one or more of the preceding claims, characterized in that the chisel point (10) has an axis at an angle α in relation to the drilling unit, the angle being α=0 to 20°.
 14. The use as claimed in at least one of claims 8 to 12, characterized in that the drill head has an asymmetric nozzle arrangement.
 15. A drilling device having a drill head (4) which has a chisel point (10), the chisel point (10) having an axis at an angle α in relation to the drilling unit, characterized in that the angle is α=0 to 20°. 